CrowdSec decision list fetched, kept, and its clients banned until the decision ends (closes #106)

SWWAF_CROWDSEC_LAPI_URL and SWWAF_CROWDSEC_LAPI_KEY name an engine whose
decision list, <url>/v1/decisions, is fetched every minute with the key in
X-Api-Key and kept as a blocklist is: used while a fetch fails, and across
restarts through reputation.json. Ban decisions on an Ip or a Range end at
the fetch time plus their duration. A listed client's request is refused and
bans its netblock with the cause crowdsec until the decision ends; bans.json,
ban notes and metrics take the cause.

Judgement call: fetched every minute, not a setting.
Judgement call: a crowdsec ban never lengthens a limit ban.
Judgement call: a lifted crowdsec ban is remade while its decision lasts.

Model: opus-5-5

internal/metrics/metrics.go

@@ -154,7 +154,9 @@ func New(topN int, instanceName string) *Metrics {
 func (m *Metrics) AddBansAndClients(
 	ledger *bans.Ledger, limiter *ratelimit.Limiter, now func() time.Time,
 ) {
-	for _, cause := range []string{bans.CauseLimit, bans.CauseAttack, bans.CauseAdmin} {
+	for _, cause := range []string{
+		bans.CauseLimit, bans.CauseAttack, bans.CauseAdmin, bans.CauseCrowdSec,
+	} {
 		m.registry.MustRegister(prometheus.NewCounterFunc(prometheus.CounterOpts{
 			Name:        "smallwebwaf_bans_made_total",
 			Help:        "Bans made, by cause.",
@@ -263,16 +265,16 @@ const sourceLabel = "source"
 
 // AddReputation adds the metrics of the lists fetched from URLs and of the
 // DNSBL zones, by source, each list's URL or each zone, its key masked as
-// config.MaskZoneKey masks it: the requests whose client a blocklist, a
-// zone's verdict or AbuseIPDB's score lists, which ReputationHit counts,
-// and, read from lists and dnsbl as the metrics are asked for, for a list,
-// the fetches that failed and when the copy in use was fetched, and for a
-// zone, the queries made and those that failed. It is called once, before
-// ReputationHit.
+// config.MaskZoneKey masks it: the requests whose client a blocklist, the
+// CrowdSec decision list, a zone's verdict or AbuseIPDB's score lists,
+// which ReputationHit counts, and, read from lists and dnsbl as the
+// metrics are asked for, for a list, the fetches that failed and when the
+// copy in use was fetched, and for a zone, the queries made and those that
+// failed. It is called once, before ReputationHit.
 func (m *Metrics) AddReputation(lists *reputation.Lists, dnsbl *reputation.DNSBL) {
 	m.reputationHits = counterVec("smallwebwaf_reputation_hits_total",
-		"Requests whose client a blocklist, a DNSBL zone or AbuseIPDB lists, by "+
-			"the blocklist's URL, the zone, or abuseipdb.",
+		"Requests whose client a blocklist, the CrowdSec decision list, a DNSBL "+
+			"zone or AbuseIPDB lists, by the list's URL, the zone, or abuseipdb.",
 		[]string{sourceLabel})
 	m.registry.MustRegister(m.reputationHits)
 
@@ -325,8 +327,9 @@ func (m *Metrics) AddAbuseIPDB(abuseIPDB *reputation.AbuseIPDB) {
 	)
 }
 
-// ReputationHit counts a request whose client source lists: a blocklist,
-// by its URL, a DNSBL zone, its key masked, or AbuseIPDB, abuseipdb.
+// ReputationHit counts a request whose client source lists: a blocklist
+// or the CrowdSec decision list, by its URL, a DNSBL zone, its key masked,
+// or AbuseIPDB, abuseipdb.
 func (m *Metrics) ReputationHit(source string) {
 	m.reputationHits.WithLabelValues(source).Inc()
 }